/// [Largest product in a grid](https://projecteuler.net/problem=11)
fn main() {
    let num_str = "08 02 22 97 38 15 00 40 00 75 04 05 07 78 52 12 50 77 91 08
                   49 49 99 40 17 81 18 57 60 87 17 40 98 43 69 48 04 56 62 00
                   81 49 31 73 55 79 14 29 93 71 40 67 53 88 30 03 49 13 36 65
                   52 70 95 23 04 60 11 42 69 24 68 56 01 32 56 71 37 02 36 91
                   22 31 16 71 51 67 63 89 41 92 36 54 22 40 40 28 66 33 13 80
                   24 47 32 60 99 03 45 02 44 75 33 53 78 36 84 20 35 17 12 50
                   32 98 81 28 64 23 67 10 26 38 40 67 59 54 70 66 18 38 64 70
                   67 26 20 68 02 62 12 20 95 63 94 39 63 08 40 91 66 49 94 21
                   24 55 58 05 66 73 99 26 97 17 78 78 96 83 14 88 34 89 63 72
                   21 36 23 09 75 00 76 44 20 45 35 14 00 61 33 97 34 31 33 95
                   78 17 53 28 22 75 31 67 15 94 03 80 04 62 16 14 09 53 56 92
                   16 39 05 42 96 35 31 47 55 58 88 24 00 17 54 24 36 29 85 57
                   86 56 00 48 35 71 89 07 05 44 44 37 44 60 21 58 51 54 17 58
                   19 80 81 68 05 94 47 69 28 73 92 13 86 52 17 77 04 89 55 40
                   04 52 08 83 97 35 99 16 07 97 57 32 16 26 26 79 33 27 98 66
                   88 36 68 87 57 62 20 72 03 46 33 67 46 55 12 32 63 93 53 69
                   04 42 16 73 38 25 39 11 24 94 72 18 08 46 29 32 40 62 76 36
                   20 69 36 41 72 30 23 88 34 62 99 69 82 67 59 85 74 04 36 16
                   20 73 35 29 78 31 90 01 74 31 49 71 48 86 81 16 23 57 05 54
                   01 70 54 71 83 51 54 69 16 92 33 48 61 43 52 01 89 19 67 48";
    let mut num_mat: Vec<Vec<u32>> = vec![];
    for line in num_str.lines() {
        let mut tmp: Vec<u32> = vec![];
        for item in line.split_whitespace() {
            tmp.push(item.parse().unwrap());
        }
        num_mat.push(tmp);
    }
    // for rows in &num_mat {
    //     println!("{:?}", rows);
    // }
    for length in &[4] {
        let max = largest_product_in_a_grid(&num_mat, *length);
        println!("The greatest product of {} adjacent numbers is {}", length, max);
    }
}
fn largest_product_in_a_grid(num_mat: &Vec<Vec<u32>>, length: usize) -> u32 {
    let mut max_mul = 0;
    for rows in num_mat {
        for i in 0..(rows.len() - length) {
            let mut tmp = 1;
            for k in 0..length {
                tmp *= rows[i + k];
            }
            if tmp > max_mul {
                max_mul = tmp;
            }
        }
    }
    for i in 0..(num_mat.len() - length) {
        for j in 0..num_mat[0].len() {
            let mut tmp = 1;
            for k in 0..length {
                tmp *= num_mat[i + k][j];
            }
            if tmp > max_mul {
                max_mul = tmp;
            }
        }
        for j in 0..(num_mat[0].len() - length) {
            let mut tmp1 = 1;
            let mut tmp2 = 1;
            for k in 0..length {
                tmp1 *= num_mat[i + k][j + k];
                tmp2 *= num_mat[i + k][j + length - k - 1];
            }
            if tmp1 > max_mul {
                max_mul = tmp1;
            }
            if tmp2 > max_mul {
                max_mul = tmp2;
            }
        }
    }
    max_mul
}
